This invention relates to heat exchangers of the type commonly referred to as charge air coolers for use in reducing the temperature of charge air supplied to a combustion engine. More specifically, this invention relates to an improved charge air cooler in conjunction with a simplified arrangement for mounting the charge air cooler securely into the intake manifold of a combustion engine.
Charge air cooler heat exchangers in general are known in the art and comprise a heat exchanger core mounted along the flow path of charge air supplied to a combustion engine. This charge air comprises ambient air which has been compressed by apparatus such as a supercharger or turbocharger to provide an increased mass flow of air to the engine to permit the engine to combust increased quantities of fuel and thereby operate at an increased level of power and performance. However, compression of the ambient air also elevates the air temperature such that the charge air has a relatively high temperature which, if not reduced, undesirably increases the total engine heat load. It is therefore desirable to cool the charge air prior to supply thereof to the engine. Charge air coolers are provided for this purpose and typically include a plurality of lightweight heat transfer elements defining flow paths to pass the charge air in heat transfer relation with a suitable coolant, such as ambient air or a liquid coolant, prior to ingestion of the charge air by the engine.
In many engine systems, it is both convenient and desirable to mount the charge air cooler directly into an intake manifold of the engine. In this configuration, the charge air passing through the intake manifold simultaneously passes through an air flow path in the charge air cooler immediately prior to ingestion by the engine. Suitable plumbing fixtures are provided for circulating the coolant through a separate flow path in the charge air cooler to controllably reduce the temperature of the charge air. For example, it is known to circulate liquid coolant from an engine-cooling radiator through the charge air cooler to reduce the temperature of the charge air.
According to conventional installation techniques, the charge air cooler is mounted within the intake manifold of the engine by a plurality of bolts which extend through opposite sides of the manifold and are fastened into appropriate threaded structures carried on the opposite sides of the charge air cooler. However, this mounting technique requires the charge air cooler to include relatively thick and structurally rigid side plates capable of supporting the bolt-receiving threaded structures and of accommodating mounting forces applied to the cooler by the mounting bolts. These thick side plates increase the overall weight and cost of the cooler and have a coefficient of thermal expansion somewhat different from that of the relatively thin and lightweight heat transfer elements defining the fluid flow paths. As a result, the charge air cooler is subjected to relatively high mechanical and thermal stresses during use wherein these stresses tend to reduce the overall operating life of the cooler. In addition, the relatively thick side plates occupy a significant portion of the charge air cooler volume which could otherwise be occupied by heat transfer elements to improve heat transfer capability.
In most combustion engine systems, the intake manifold is mounted closely alongside the engine thereby making access to the charge air cooler mounting bolts extremely difficult at one side of the intake manifold. For example, the intake manifold typically includes an outboard wall facing away from the engine whereby the mounting bolts fastened therethrough are accessible and an inboard wall facing toward the engine whereby the mounting bolts fastened therethrough are substantially inaccessible when the intake manifold is mounted on the engine. Accordingly, the charge air cooler is not easily mounted within the intake manifold when the intake manifold is mounted on the engine. Instead, the charge air cooler is first bolted into the intake manifold and then the cooler-manifold assembly is bolted as a unit on to the engine. Unfortunately, the combined size and weight of the cooler-manifold assembly makes this procedure extremely difficult and time consuming and thereby results in a substantial increase in manufacturing costs.
The present invention overcomes the problems and disadvantages of the prior art by providing an improved charge air cooler and mounting arrangement therefor wherein the charge air cooler is quickly and easily installed into an intake manifold already mounted on an engine and wherein the cooler includes structural members for receiving mounting bolts in the absence of relatively thick and structurally rigid side plates to minimize mechanical and/or thermal loading of heat transfer elements and to permit optimized use of heat transfer elements across the width of the cooler.